Senior Backend Developer - Symfony

At Velstar, we build robust, scalable digital commerce solutions for ambitious brands. We're looking for a Senior Backend Developer to lead the design and development of high-performance web applications and help shape the technical direction of our backend team., As a Senior Backend Developer, you'll act as a technical leader within the team, driving architecture, improving performance, and ensuring high coding standards across projects. You'll work closely with frontend developers, DevOps and product teams to deliver scalable, secure and reliable applications.

Alongside delivery, you'll mentor junior and mid-level developers, contribute to best practices, and help guide technical decisions from concept through to deployment.

What you'll be doing

• Designing and architecting scalable, high-performance applications
• Leading development of complex features and new systems
• Making key technical decisions and establishing backend best practices
• Optimising performance across databases, caching and application layers
• Improving API performance and overall application speed
• Implementing robust security practices (authentication, authorisation, vulnerability prevention)
• Conducting deep troubleshooting and resolving critical issues
• Mentoring developers through code reviews, guidance and knowledge-sharing
• Collaborating with Product, Frontend and DevOps teams to align solutions with business goals
• Supporting estimation, planning and development workflows
• Ensuring strong test coverage and stable production releases

Do you have experience in Test-driven development?, You're a highly capable backend developer who combines deep technical expertise with strong ownership and leadership. You're comfortable guiding decisions, improving standards, and supporting others' growth.

You'll likely have:

• 5+ years' experience in backend development
• Deep expertise in PHP and Symfony (including modern Symfony versions)
• Strong understanding of Symfony components, architecture and best practices
• Advanced SQL and Doctrine ORM knowledge
• Experience with performance optimisation, caching and scalable systems
• Solid testing practices (PHPUnit, TDD mindset)
• Experience designing scalable, maintainable architectures
• Confidence mentoring and reviewing others' code

Nice to have:

• Experience with API Platform
• Familiarity with Redis, Elasticsearch or other NoSQL tools
• Experience with event-driven or asynchronous architectures
• Some frontend awareness (React / Next.js)
• eCommerce or agency experience, * Hybrid working (minimum 3 days per week in our Liverpool or Leeds office)
• A senior role with real technical influence and ownership
• Complex, high-traffic projects that challenge and grow your skills
• A collaborative team that values quality and continuous improvement
• Clear progression opportunities for senior engineers

If you enjoy building scalable systems, mentoring others and solving meaningful technical problems, we'd love to hear from you.